A virtual universe (VU) is an interactive simulated environment accessed by multiple users through an online interface. Users inhabit and interact in the VU via avatars, which are a user's representation of himself or herself. These representations can be in the form of a three-dimensional model, a two-dimensional icon, a text construct, a user screen name, etc. Although there are many different types of VUs, there are several features many VUs generally have in common. These features include, for example,                Shared Space: the VU allows many users to participate at once;        Graphical User Interface: the VU depicts space visually, ranging in style from 2D “cartoon” imagery to more immersive 3D environments;        Immediacy: interaction takes place in real time;        Interactivity: the VU allows users to alter, develop, build, or submit customized content;        Persistence: the VU's existence continues regardless of whether individual users are logged in; and        Socialization/Community: the VU allows and encourages the formation of social groups such as teams, guilds, clubs, cliques, housemates, neighborhoods, etc.        
When interacting in VUs it is often difficult for a user to accurately represent himself or herself in the VU via an avatar. Moreover, it is even more difficult for a user to continuously update his or her avatar to represent the user's ever changing physical and/or behavioral characteristics. This lack of similarity between the user and his or her avatar detracts from the user's virtual experience.
In addition to detracting from the user's virtual experience, the inability of the user to accurately represent himself or herself via an avatar makes it difficult for others to verify and/or authenticate the user. Moreover, even when an avatar does accurately resemble his or her owner, the resemblance may not provide enough verification for business transactions, meetings, etc., that may occur within a VU.